Fluorothermoplastics (i.e., melt-processable fluoropolymers) can be processed in a variety of manners such as extrusion, injection molding, compression molding, transfer molding and blow molding. Fluorothermoplastics typically have properties such as, for example, low gas permeability, chemical inertness, and low surface energy and have been used in applications ranging from wiring insulation to valves, tubes and pipes, low permeation tubing, radiation resistant film, films, textiles, and papermaking. For example, adhering a fluorothermoplastic film to a substrate typically confers a degree of solvent, water, and weathering resistance to the substrate. In such applications, the choice of fluorothermoplastics that may be used for a specific application may be restricted by the degree of adhering that may be attained between the fluorothermoplastic and the substrate.
Some physical properties of fluorothermoplastics typically differ from fluoropolymers that cannot be melt-processed. For example, polytetrafluoroethylene (PTFE)) has such a high melting point that it cannot be melt-processed and is typically sintered instead, resulting in porous materials that, especially as films, typically have a degree of gas permeability in excess of that observed with a nonporous fluorothermoplastic.
In general, low surface energy fluorothermoplastics are known for their poor adhesion to dissimilar materials such as, for example, pressure sensitive adhesives. To overcome this problem, various methods for improving the adhesive properties of fluorothermoplastics have been heretofore investigated. Those methods include modifying the surface of the fluorothermoplastic (e.g., by radiation or chemical treatment), and interposing a special layer (e.g., a tie layer or primer) between the pressure sensitive adhesive and the fluorothermoplastic. However, such methods require additional steps and add complexity and cost to the finished adhesive articles.